Questions of sexual ethics are immensely contested in highly religious Christian communities. The liberalization of sexual ethics in modern societies is countered by the continuing and in some cases growing influence of fundamentalist attitudes. Based on the results of the triangular study ‚Sexual attitudes and behaviors of (highly) religious Christians', the paper will analyze which patterns of change can be identified in the sexual ethics of highly religious Christians. In particular, the results of a discourse analysis, which examined Christian sexual advice books from the period 1977 to 2021, as well as the results of a quantitative survey, which investigated the connection between sexual ethical attitudes, denominational affiliations, fundamentalism and the change in one's own theological convictions, will be taken into account.